Flow controlling device for refrigerating systems



Feb. 20, 1940. STEENSTRUP 2,191,328

FLOW `CONTROLLING DEVICE FOR REFRIGERATING SYSTEMS Filed April 1, 1957 Inventor- Christian Steen stmp His Attorney.

Patented Feb. 20, 1940 UNITED STATES PATENT OFFICE FLOW CONTROLLING DEVICE FOR REFRIGERATIN G SYSTEMS tion of New York Application April 1, 1937, Serial No. 134,325

6 Claims.

My invention relates to refrigerating systems of the type having a valve or flow controlling device for the purpose of admitting refrigerant to the low pressure side `of the system from the 5 high pressure side thereof. K

In connection with refrigerating systems adapted to cool a compartment, such as a domestic refrigerator, an evaporator which is supplied with refrigerant from some external source is ordinarily placed within` the compartment. It is necessary to provide a device for controlling the flow of refrigerant to the evaporator, such as a valve or the like, which maintains the necessary difference of pressure between the evapl orator and the source of refrigerant supply.

When the refrigerant passes from the high pressure side to the low pressure side of this valve,

a portion of the refrigerant vaporizes due to the sudden change in pressure to which it is sub- 20 jected and absorbs heat which lowers the temperature of the valve'seat and the cooperating movable valve element. Any slight trace of moisture present in the refrigerant is frozen upon coming into contact with the cold surfaces of the f valve seat and the cooperating valve element, causing deposits of frost to become attached thereto. This accumulation of frost on the valve seat and the cooperating valve element impairs the operation of the valve and prevents the refrigerating system from producing refrigeration.

It is an object of my invention to provide an improved refrigerating system having an arrangement utilizing heat in a compartment cooled by the system for preventing accumulation of frost i in the interior of a refrigerant flow controlling device employed in the system.

Another object of my invention is to provide an improved refrigerant flow controlling device of the above character having an arrangement utilizing heat for preventing accumulation of frost on a valve element in the device, the device being so constructed and arranged that heat ilow to other parts of the device operated at a lower temperature is substantially prevented.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity inthe claims annexed to 50 and forming a part of this specification.

For a, better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a side elevation of a refrigerator cabinet incorporating a refrigerating sys- ,1 tem embodying my invention; Fig. 2 is an enlarged sectional elevation of a refrigerant ow controlling device employed in the refrigerating system shown in Fig. 1; and Fig. 3 is a sectional view along the line 3-3 of the float controlling device shown in Fig. 2. showing the arrange- 5 ment of a finned structure carried by the device. Referring to the drawing in Fig. 1, I have shown the upper portion of a heat insulated refrigerator cabinet I0 of the household type having a food storage compartment II provided with a removable top Wall I2, the compartment being cooled by a refrigerating system such as a unitary refrigerating machine. 'I'he refrigerating machine is mounted on the removable top wall I2 and includes a cooling unit or evaporator I3 attached 15 to the inner liner I 4 of the removable top Wall I2, which is arranged to cool the compartment I I disposed below the removable top wall I2V and also to make ice or freeze other articles placed within the evaporator. The machine also includes a motor and a compressor arranged within an enclosing casing I5 mounted on the top wall l2. -Gaseous refrigerant is compressed by `the compressor in the enclosing casing I5 and discharged into an air -cooled condenser I6 of 25 the natural draft type supported about the enclosing casing I5 upon an annulus of fins. The compressedy refrigerant in passing through the condenser I6 is cooled' and condensed into a liquid and then flows through a conduit I1 into a float 30 valve chamber I 8 which is mounted in the removable top wall I2 and embedded in heat insulation I9. The liquid refrigerant accumulates in the float valve chamber I8 and actuates a float 20 therein to control the flow of liquid refrig- 35 erant through a conduit 2I into the evaporator I3. The liquid refrigerant in the evaporator I3 is vaporized due to the absorption of heat in the compartment II and then withdrawn from the evaporator by the compressor through a conduit 22, a heat exchange device 23, and a conduit 24 extending through the bottom wall of the enclosing casing I5. This cycle of operation is continuously repeated during the operation of the machine until the compartment I I is cooled to the desired temperature.

The construction of the float valve is best shown in Fig. 2. The float valve chamber AI8 comprises a cup-shaped receptacle 25 and an inverted cup-shaped top 26 secured thereto. 'Ihe 50 receptacle 25 is welded in a flanged opening in a metal outer wall 21 of the removable top wall I2, as indicated at 23, and is embedded in the y heat insulation I9 arranged between the metal outer wall 21 and the inner liner Il of the removable top wall 2. A conduit 29 is secured in an opening inthe bottom wall of the receptacle 25 and extends downwardly therefrom through the heat insulation I9 and the inner liner I4 into the upper portion of the compartment II. A valve 38 for controlling the supply of refrigerant to the evaporator I3 through the conduit 2| is arranged in the conduit 29 adjacent the lower end thereof. The valve 38 includes a plug 3| provided with a passage therethrough having a seat 3Ia in the upper surface thereof. An integral upstanding lug is formed on the plug 3| and a passage 32 is formed therein for guiding the movement of a valve element 33 which cooperates with the valve seat 3|a.

The valve element 33 is controlled by the float 28 arranged in the oat valve chamber |8, the oat 28 being pivotally mounted at 34 upon an arm 35 which is in turn pivotally mounted at 36 upon the upper end of the conduit 29 extending into the receptacle 25. During ordinary operation, the oat 28 rises and falls in accordance with variations of the level of the liquid refrigerant in the oat chamber I8 and the movements of the float are transmitted tothe valve element 33 by a link 31 pivotally connected between the arm 35 and the valve element 33 at38 and 39, respectively.

It willfbe understood that the fioat chamber I8 is subject to the'high temperature and pressure in the condenser I6 of the refrigerating system and that the evaporator I3 is maintained at a low temperature and pressure by the compressor so that the liquid refrigerant in the evaporator is vaporized at the desired rate. When the float rises, liquid refrigerant passes through the valve 38. A portion of this refrigerant is suddenly vaporized due to the reduction in pressure to which it is subjected, and absorbs heat which lowers the temperature of the valve seat 3|a and the cooperating valve element 33. Any

slight trace of moisture present in the refrigerant will be frozen upon coming into contact with the cold surfaces of the valve seat and the cooperating valve element, causing deposits of frost to accumulate thereon. In order to prevent accumulation of frost upon the valve seat 3Ia and the cooperating valve element' 33 and the resulting impaired operation of the valve 38, a fin structure 48 is disposed about the lower end of the conduit 29 in which the valve 38 is arranged and in heat exchange relationship therewith. As best shown in Fig. 3, this iin structure 40 comprises a plurality of U-shaped fins 48a disposed annularly about the conduit 29 and brazed or welded thereto. Also a iin structure 4|, similar to the finned structure 48, is carried by the conduit 2| adjacent the lower end of the conduit 29, and is secured thereto in the same manner. Thus, the fin structures 48 and 4I are disposed in the vicinity of the valve 38.

The finned structures 48 and 4| are located in the upper portion of the compartment II adjacent the inner liner I4 of the removable top wall I2 of the cabinet I8, asthe air circulated in the compartment IIv is warmest in this portion of the compartment. Heat is absorbed by the nned structure 48 and is conducted through the v 33. Furthermore, as the heat absorbed by the iinned structures 48 and 4| is taken from the air circulated in the compartment II, this arrangement is eective to cool the compartment.

In refrigerating systems the eflciency increases with decrease in the temperature of the condenser and consequentdecrease in the temperature of the liqueed refrigerant. The vaporized gaseousv refrigerant withdrawn from the evaporator is at a temperature considerably below that of the liquid refrigerant supplied to the oat valve chamber to the condenser. In order to effect a heat transfer between the cold gaseous refrigerant and the warm liquid refrigerant, the heat exchange device 23 is arranged in good thermal conducting relationship with the conduit 29. The heat exchangel device 23 comprises a number of turns of a conduit 23a disposed about the conduit 29 between the iioat valve chamber I8 and the valve 38, the conduit 23a having substantially a square cross-section and being interposed in the low pressure side of the refrigerating system between the conduits 22 and 24.

The heat exchange device 23 effects a precooling of the liquid refrigerant in the conduit 29 on the supply side of the valve 38 which improves the efficiency of the refrigerating system and is effective to minimize vaporization of the liquid refrigerant in passing through the-valve 38, and the attendant production of frost on the valve seat and cooperating valve element should there bea slight trace of moisture inl the refrigerant.- In order to minimize the transfer of heat into the compartment from the float valve chamber I8 and the warm liquid refrigerant therein, the conduit 29 and the link 3'I connected to the valve element 33 are made of a material having low heat conductivity, such, for example, as the copper-nickel alloy sold under the tradename Monel metal. The portion of the conduit 29 between the valve 38 and the heat exchange device 23 is effective to minimize the transfer of heat from the valve to the heat exchange device due to the low heat conductivity of this conduit. v

During operation of the refrigerating system illustrated, the liquid refrigerant supplied by the condenser I6 accumulates within the oat valve chamber I8 as it is liquefied. If the valve element 33 occupies the position relative to the valve seat 3Ia. shown in Fig. 2, liquid refrigerant will ilow from the float valve chamber I8 through the conduit 29 and-the valve 38 until sufficient refrigerant has passed to permit the oat 28 to drop and close the valve 38. As the liquid refrigerant flows through the conduit 29 it is cooled by the heat exchange `device 23 to substantially the temperature of the valve 38. As the liquid refrigerant passes through the valve 38 to be supplied to the evaporator I3, a portion of the liquid refrigerant is vaporized which tends to lower the temperature of the valve seat 3Ia and the cooperating valve element 33. However, sufcient heat is absorbed by the finned structures 48 and 4| in the compartment I and conducted to the valve 38 to prevent the temperature of the surfaces of the valve seat and the cooperating valve element from being lowered 'to a temperature such that frost will accumulate therein should there be a slight trace of moisture in the refrigerant.

Although I have shown and described my invention in connection with a refrigerating system of the mechanical type, it will be understood that it is also applicable in connection with other refrigerating systems and I do not, therefore, desire my invention to be limited tothe particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigerating system including a compartment to be cooled, an evaporator thermally associated with said compartment, a flow controlling device in said compartment, -means for supplying refrigerant to said evaporator through said ow controlling device, and means in the vicinity of said flow controlling device supplying heat to said flow controlling device for preventing accumulation of frost therein.

2. A refrigerating system including a compartment to be cooled, an evaporator thermally associated with said compartment, a flow controlling device in said compartment, means for supplying refrigerant to said evaporator through said ow controlling device, and means including a nned structure carried by said flow controlling device in heat exchange relationship therewith for preventing accumulation of frost in said flow controlling device, said last-mentioned means utilizing heat conducted to said flow controlling device from the interior of said compartment.

3. A refrigerating system including a compartment to be cooled, an evaporator thermally associated with said compartment, a valve in said compartment, means for supplying refrigerant to said valve, means including aconduit for conducting refrigerant to said evaporator from said valve, and means including a finned structure arranged in heat exchange relationship with said valve and a second nned structure arranged in heat exchange relationship with said conduit adjacent said valve for preventing accumulation of frost in said valve, said last-mentioned means utilizing heat conducted to said valve from the interior of said compartment.

4. A refrigerating system including a compartment to be cooled, an evaporator thermally associated with said compartment, a flow controlling device in said compartment, means for supplying refrigerant to said evaporator through said flow controlling device and for maintaining a body of liquid refrigerant on the supply side of said flow controlling device, means for cooling a portion of said body of liquid refrigerant, means in the Vicinity of said flow controlling device supplying heat to said flow controlling device for preventing accumulation of frost therein, and means of low heat conductivity for conducting refrigerant from said body of liquid refrigerant to said flow controlling device.

5. A ow controlling device for a refrigerating system comprising a float chamber having a oat therein, a conduit extending from said oat chamber, a valve in said conduit remote from said float chamber, means utilizing the movement of said float for controlling` said valve, and a finned structure carried by said conduit in heat exchange relationship with said valve.

6. A ilow controlling device for a refrigerating system comprising a oat chamber having a float therein, a conduit extending from said float chamber, a valve in said conduit remote from said float chamber, means utilizing the movement of said iioat for controlling said valve, a second conduit communicating with said valve, a finned structure carried by said first mentioned conduit in heat exchange relationship with said valve, and a second nned structure carried by said second mentioned conduit adjacent said valve and in heat exchange relationship therewith.

CHRISTIAN STEENSTRUP. 

